NullPointerException during Project Scan when "Discover merge requests from forks" is used with "Build MRs of forks that are not mirrors"

[csrichter]

Jenkins and plugins versions report

Environment

Jenkins: 2.452.3
OS: Windows Server 2016 - 10.0
Java: 21.0.3 - Eclipse Adoptium (OpenJDK 64-Bit Server VM)
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blueocean-rest-impl:1.27.14
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xunit:3.1.4

What Operating System are you using (both controller, and any agents involved in the problem)?

Windows Server 2016

Reproduction steps

1. configure gitlab group with "Discover merge requests from origin" and "Discover merge requests from forks" with "Build MRs of forks that are not mirrors" enabled
2. scan a GitLab group without any forks

Expected Results

jobs for "discover from origin" are created and "Discover merge requests from forks" is ignored, because there are no forks

Actual Results

exception in scan log:

ERROR: Failed to create or update a subproject sandbox/gitlab-eval
java.lang.NullPointerException: Cannot invoke "org.gitlab4j.api.models.Project.getId()" because the return value of "org.gitlab4j.api.models.Project.getForkedFromProject()" is null
	at io.jenkins.plugins.gitlabbranchsource.GitLabSCMSource.lambda$retrieve$1(GitLabSCMSource.java:355)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:178)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1708)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682)
	at io.jenkins.plugins.gitlabbranchsource.GitLabSCMSource.retrieve(GitLabSCMSource.java:362)
	at jenkins.scm.api.SCMSource._retrieve(SCMSource.java:372)
	at jenkins.scm.api.SCMSource.fetch(SCMSource.java:326)
	at jenkins.branch.MultiBranchProjectFactory$BySCMSourceCriteria.recognizes(MultiBranchProjectFactory.java:262)
	at jenkins.branch.OrganizationFolder$SCMSourceObserverImpl$1.recognizes(OrganizationFolder.java:1356)
	at jenkins.branch.OrganizationFolder$SCMSourceObserverImpl$1.complete(OrganizationFolder.java:1371)
	at jenkins.scm.api.trait.SCMNavigatorRequest.process(SCMNavigatorRequest.java:252)
	at jenkins.scm.api.trait.SCMNavigatorRequest.process(SCMNavigatorRequest.java:202)
	at io.jenkins.plugins.gitlabbranchsource.GitLabSCMNavigator.visitSources(GitLabSCMNavigator.java:309)
	at jenkins.branch.OrganizationFolder.computeChildren(OrganizationFolder.java:530)
	at com.cloudbees.hudson.plugins.folder.computed.ComputedFolder.updateChildren(ComputedFolder.java:269)
	at com.cloudbees.hudson.plugins.folder.computed.FolderComputation.run(FolderComputation.java:167)
	at jenkins.branch.OrganizationFolder$OrganizationScan.run(OrganizationFolder.java:915)
	at hudson.model.ResourceController.execute(ResourceController.java:101)
	at hudson.model.Executor.run(Executor.java:442)

Anything else?

No response

Are you interested in contributing a fix?

No response

[Turiok]

Hi @csrichter ,

Can you close this issue if it's corrected?

[csrichter]

our workaround was to remove the fork relationship in GitLab so our repositories are no longer forks

i have not re-tested since applying this workaround

[csrichter]

i have re-tested now and run into the same NullPointerException

the behaviour configuration for the group is as follows:

• Discover subgroup projects
• Discover branches
  • All Branches
• Discover merge requests from forks
  • Build MRs of forks that are not mirrors
    • true
    • this is the option that seems to cause the Nullpointer when scanning repos that are not forks
• Discover merge requests from origin